react-native-art 绘制波浪动画

gif.gif

直接看代码吧
波浪组件WaveView.js

import React, {Component} from 'react';
import {View,ART,Dimensions} from 'react-native';

export class HcdWaveView extends Component {
  static defaultProps = {
    surfaceWidth: Dimensions.get('window').width,
    surfaceHeigth: 189,
  }

  constructor(props) {
    super(props);
    this.surfaceWidth = this.props.surfaceWidth;
    this.surfaceHeigth = this.props.surfaceHeigth;
    this.state = {
      a: 1.5,
      b: 0,
      increase: false,
    };
  }

  componentDidMount() {
    this.intervalTimer = setInterval(() => {
      var a = this.state.a
      var b = this.state.b
      var increase = this.state.increase
      if (increase) {
        a += 0.01
      } else {
        a -= 0.01
      }
      if (a <= 1) {
        increase = true
      }
      if (a >= 1.5) {
        increase = false
      }
      b += 0.1
      this.setState({
        a: a,
        b: b,
        increase: increase
      })
    }, 140)
  }

  componentWillUnmount() {
    this.intervalTimer && clearInterval(this.intervalTimer)
  }

//绘制渐变的背景
  artBg() {
    const w = this.props.surfaceWidth
    const h = this.props.surfaceHeigth
    const pathBase = new ART.Path()
    .moveTo(0,0) // 改变起点为 0,5 。默认为0,0
    .lineTo(w,0) // 目标点
    .lineTo(w,h) // 目标点
    .lineTo(0,h) // 目标点
    .close();
    let colors = [ "#0063cd", "#00a7f4", ];
    let linearGradient = new ART.LinearGradient(colors, 0, 0, 90, 280);

    return 
      
        
        {this.wave(175, '#1fb6f8')}
        {this.wave1('#67d2fd')}
        {this.wave2('#fff')}
      
    
  }

  // 正弦曲线公式： y = A sin(Bx + C) + D

  // A 控制振幅，A 值越大，波峰和波谷越大，A 值越小，波峰和波谷越小；
  // B 值会影响周期，B 值越大，那么周期越短，B 值越小，周期越长。
  // C 值会影响图像左右移动，C 值为正数，图像右移，C 值为负数，图像左移。
  // D 值控制上下移动。

//绘制波浪
  wave(startY, fl){
    const a = this.state.a
    const b = this.state.b
    const w = this.props.surfaceWidth
    const h = this.props.surfaceHeigth
    const pathBase = new ART.Path()
    pathBase.moveTo(0,startY) // 改变起点为 0,5 。默认为0,0
    for( var i = 0; i <= w / 68; i += 0.1 ){
      var x = i * 70;
      var y = a * Math.cos( i + b ) * 10 + startY;
      pathBase.lineTo( x, y );
    }
    pathBase.lineTo(w,h) // 目标点
    pathBase.lineTo(0, h);
    pathBase.close();
    return 
  }

  wave1(fl){
    const a = this.state.a
    const b = this.state.b
    const w = this.props.surfaceWidth
    const h = this.props.surfaceHeigth
    const pathBase = new ART.Path()
    pathBase.moveTo(0,180) // 改变起点为 0,5 。默认为0,0
    for( var i = 0; i <= w/68; i += 0.1 ){
      var x = i * 70;
      var y = a * Math.sin( i + b ) * 10 + 175;
      pathBase.lineTo( x, y );
    }
    pathBase.lineTo(w,h) // 目标点
    pathBase.lineTo(0, h);
    pathBase.close();
    return 
  }
  wave2(fl){
    const a = this.state.a
    const b = this.state.b
    const w = this.props.surfaceWidth
    const h = this.props.surfaceHeigth
    const pathBase = new ART.Path()
    pathBase.moveTo(0,175) // 改变起点为 0,5 。默认为0,0
    for( var i = 0; i <= w/98; i += 0.1 ){
      var x = i * 100;
      var y = a * Math.sin( i + b ) * 10 + 175;
      pathBase.lineTo( x, y );
    }
    pathBase.lineTo(w,h) // 目标点
    pathBase.lineTo(0, h);
    pathBase.close();
    return 
  }

  render() {
    return (
      
        {this.artBg()}
      
    )
  }
}